Enhancing positioning via measurement batching

ABSTRACT

Example methods, apparatuses, and/or articles of manufacture are disclosed herein that may be utilized, in whole or in part, to facilitate and/or support one or more operations and/or techniques for enhancing positioning, which may include E911 positioning, via measurement batching, such as for use in or with mobile communication devices, for example.

BACKGROUND 1. Field

The present disclosure relates generally to position or locationestimations of mobile communication devices and, more particularly, toenhancing positioning via measurement batching for use in or with mobilecommunication devices.

2. Information

Mobile communication devices, such as, for example, cellular telephones,portable navigation units, laptop computers, personal digitalassistants, or the like are becoming more common every day. Certainmobile communication devices, such as, for example, location-awarecellular telephones, smart telephones, or the like may assist users inestimating their geographic locations by providing positioningassistance parameters obtained or gathered from various systems. Forexample, in an outdoor environment, certain mobile communication devicesmay obtain an estimate of their geographic location or so-called“position fix” by acquiring wireless signals from a satellitepositioning system (SPS), such as the global positioning system (GPS) orother like Global Navigation Satellite Systems (GNSS), cellular basestation, etc. via a cellular telephone or other wireless communicationsnetwork. Acquired wireless signals may, for example, be processed by orat a mobile communication device, and its location may be estimatedusing known techniques, such as Advanced Forward Link Trilateration(AFLT), base station identification, cell tower triangulation, or thelike.

In an indoor or like environment, such as urban canyons, for example,mobile communication devices may be unable to reliably receive oracquire satellite or like wireless signals to facilitate and/or supportone or more position estimation techniques. For example, signals from anSPS or other wireless transmitters may be attenuated or otherwiseaffected in some manner (e.g., insufficient, weak, fragmentary, etc.),which may at least partially preclude their use for positionestimations. At times, a mobile communication device may obtain aposition fix by measuring ranges to three or more terrestrial wirelesstransmitter devices, such as cellular base stations, access points, etc.positioned at known locations. Ranges may be measured, for example, byobtaining a Media Access Control identifier (MAC ID) address fromwireless signals received from suitable access points and measuring oneor more characteristics of received signals, such as signal strength,round trip delay, or the like.

At times, a position fix of a mobile communication device may, forexample, be obtained in connection with one or more positioning tiles.For example, a number of wireless transmitters, indoor or otherwise, maybe grouped into a geographically-bounded area to comprise and/or bedefined via a so-called “positioning tile” or simply “tile.” A tile mayinclude positioning assistance parameters, such as locations,identities, etc. for a set of known wireless transmitters, for example,representative of and/or corresponding to a particular geographic area.As such, a mobile communication device may retrieve (e.g., access,download, etc. via a server, etc.) one or more tiles and may use one ormore associated parameters to estimate its location within an area usingone or more known techniques, such as, for example, techniques mentionedabove (e.g., triangulation, radio heat map signature matching, rangemeasurement, etc.). In some instances, positioning tiles may be employedto assist in localization of a mobile communication device in the eventof an emergency call, such as in connection with an observed timedifference of arrival (OTDOA) positioning session, as one possibleexample, in compliance with Emergency 911 (E911) mandates from theFederal Communication Commission (FCC). At times, however, accuracy ofpositioning, E911 or otherwise, employing positioning tiles may beaffected, at least in part, by lack of requisite positioning assistanceparameters within the tiles. For example, in some instances, a providedpositioning tile may lack parameters for one or more wirelesstransmitters currently observed by a mobile communication device withinan area of interest, which, in some instances, may result in less thansufficient position fixes.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive aspects are described with reference tothe following figures, wherein like reference numerals refer to likeparts throughout the various figures unless otherwise specified.

FIG. 1 is a schematic diagram illustrating features associated with animplementation of an example operating environment.

FIG. 2 is a flow diagram illustrating an implementation of an exampleprocess that may be performed to facilitate and/or support enhancingpositioning via measurement batching.

FIG. 3 is a schematic diagram of an implementation of an examplemeasurement batching approach.

FIG. 4 is a flow diagram illustrating another implementation of anexample process that may be performed to facilitate and/or supportenhancing positioning via measurement batching.

FIG. 5 is a schematic diagram illustrating an implementation of anexample computing environment associated with a mobile device.

FIG. 6 is a schematic diagram illustrating an implementation of anexample computing environment associated with a server.

SUMMARY

Example implementations relate to techniques for enhancing positioningvia measurement batching. In one implementation, a method may comprisestoring observations of radio frequency (RF) signals transmitted fromone or more wireless transmitters in an area, the observations beingstored based, at least in part, on one or more associations between theobservations; and processing the observations to obtain an estimate of alocation of a mobile device based, at least in part, on the one or moreassociations and responsive to a request for the estimate occurringsubsequent to the storing the observations.

In another implementation, an apparatus may comprise means for storingobservations of radio frequency (RF) signals transmitted from one ormore wireless transmitters in an area, the observations being storedbased, at least in part, on one or more associations between theobservations; and means for processing the observations to obtain anestimate of a location of a mobile device based, at least in part, onthe one or more associations and responsive to a request for theestimate occurring subsequent to the storing the observations.

In yet another implementation, an apparatus may comprise a communicationinterface coupled to a receiver of a mobile device to communicate withan electronic communications network and one or more processors coupledto a memory and to the communication interface, the communicationinterface and the one or more processors configured to storeobservations of radio frequency (RF) signals transmitted from one ormore wireless transmitters in an area, the observations being storedbased, at least in part, on one or more associations between theobservations; and process the observations to obtain an estimate of alocation of the mobile device based, at least in part, on the one ormore associations and responsive to a request for the estimate occurringsubsequent to the storing the observations.

In yet another implementation, a non-transitory storage medium maycomprise instructions executable by a processor to store observations ofradio frequency (RF) signals transmitted from one or more wirelesstransmitters in an area, the observations being stored based, at leastin part, on one or more associations between the observations; andprocess the observations to obtain an estimate of a location of a mobiledevice based, at least in part, on the one or more associations andresponsive to a request for the estimate occurring subsequent to thestoring the observations.

In yet another implementation, a method may comprise batching, at amobile device, multiple observations of RF signals transmitted from aplurality of unknown wireless transmitters in an area, the multipleobservations being obtained while the mobile device is positioned atmultiple different locations within the area; obtaining, via positioningassistance data, at least locations of at least some of the unknownwireless transmitters in the area, the locations being obtainedsubsequently to the batching the multiple observations; and estimating alocation of at least one wireless transmitter absent from thepositioning assistance data based, at least in part, on the subsequentlyobtained locations and the batched multiple observations.

In yet another implementation, an apparatus may comprise means forbatching multiple observations of RF signals transmitted from aplurality of unknown wireless transmitters in an area, the multipleobservations being obtained while the mobile device is positioned atmultiple different locations within the area; means for obtaining, viapositioning assistance data, at least locations of at least some of theunknown wireless transmitters in the area, the locations being obtainedsubsequently to the batching the multiple observations; and means forestimating a location of at least one wireless transmitter absent fromthe positioning assistance data based, at least in part, on thesubsequently obtained locations and the batched multiple observations.It should be understood, however, that these are merely exampleimplementations, and that claimed subject matter is not limited to theseparticular implementations.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth to provide a thorough understanding of claimed subject matter.However, it will be understood by those skilled in the art that claimedsubject matter may be practiced without these specific details. In otherinstances, methods, apparatuses, or systems that would be known by oneof ordinary skill have not been described in detail so as not to obscureclaimed subject matter.

Some example methods, apparatuses, and/or articles of manufacture aredisclosed herein that may be implemented, in whole or in part, tofacilitate and/or support one or more operations and/or techniques forenhancing positioning, which may include E911 positioning, for example,via measurement batching for use in or with mobile communicationdevices. As used herein, “mobile device,” “mobile communication device,”“location-aware mobile device,” or like terms may be usedinterchangeably and refer to any kind of special purpose computingplatform or apparatus that may from time to time have a position orlocation that changes. In some instances, a mobile communication devicemay, for example, be capable of communicating with other devices, mobileor otherwise, through wireless transmission or receipt of informationaccording to one or more communication protocols. As a way ofillustration, special purpose mobile communication devices, which mayherein be called simply mobile devices, may include, for example,cellular telephones, smart telephones, personal digital assistants(PDAs), laptop computers, personal entertainment systems, tabletpersonal computers (PC), personal audio or video devices, personalnavigation devices, radio heat map generation tools, or the like. Itshould be appreciated, however, that these are merely examples of mobiledevices that may be used, at least in part, to implement one or moreoperations and/or techniques for enhancing positioning via measurementbatching, and that claimed subject matter is not limited in this regard.It should also be noted that the terms “position” and “location” may beused interchangeably herein.

As alluded to previously, at times, a position fix of a mobile devicemay, for example, be obtained based, at least in part, on positioningassistance data that may be selectively provided to the mobile device,such as by a navigation system, location or like server, or the like. Insome instances, positioning assistance data may comprise, for example,one or more parameters descriptive of attributes of wirelesstransmitters (e.g., Wi-Fi access points, cellular base stations, etc.)positioned at known locations. These attributes may include, forexample, MAC addresses, cellular identification numbers (Cell IDs),transmission power levels, characteristics of wireless signalsindicative of received signal strength (e.g., RSSI, etc.), round-tripdelay times (e.g., RTT, etc.), etc., just to provide a few examples. Inaddition, at times, positioning assistance parameters may comprise, forexample, electronic digital map-related parameters (e.g., for additionalcontext, etc.), radio heat map values, or the like, such as for an areaof interest, indoor or otherwise. Of course, these are merely examplesof positioning assistance parameters, and claimed subject matter is notso limited. With the knowledge of one or more attributes of wirelesstransmitters, a mobile device may then estimate its location using oneor more suitable approaches, as was indicated. One technique forobtaining positioning assistance data for a mobile device may include,for example, accessing the data via a server (e.g., location server,positioning assistance server, etc.), such as through a selection of aUniform Resource Locator (URL). Another possible technique may includereceiving positioning assistance parameters from a server in response toa location request, such as in connection with an applicable positioningsession, for example.

As was also indicated, in some instances, a mobile device may obtainpositioning assistance parameters via one or more so-called “positioningtiles.” As used herein, the terms “positioning tile” or “tile” may beused interchangeably and refer to one or more parameters descriptive ofattributes of wireless transmitters grouped with respect to one or morepredefined geographically-bounded areas of uniform or non-uniformdimensions. Such attributes may include, for example, locations,transmission power levels (e.g., RSSI, etc.), timing characteristics(e.g., RTT, etc.), unique identifiers (e.g., Wi-Fi MAC address, Cell ID,etc.), etc. of wireless transmitters, such as located within and/orproximate to a particular geographically-bounded area. In operative use,a mobile device may, for example, perform a “scan,” such as an activescan, passive scan, etc. of an area to acquire signals transmitted byproximate or “visible” wireless transmitters within the area and/ordetect particular parameters encoded in the acquired signals (e.g.,unique identifiers, etc.). By way of explanation, an active scan may,for example, be performed via transmitting one or more requests, such asin the form of one or more unicast packets and receiving one or moreresponses from one or more proximate wireless transmitters, and apassive scan may, for example, be performed by “listening” for ordiscovering wireless signals broadcasted by proximate wirelesstransmitters, such as without transmitting a request. These or likescans are generally known and need not be described here in greaterdetail. Having performed a scan, a mobile device may, for example,request one or more positioning tiles, such as covering an area of arough location of the mobile device, which may be determined, at leastin part, via a location of a serving wireless transmitter (e.g., aserving cellular base station, Wi-Fi access point, etc.), such as viaCell ID and/or enhanced Cell ID positioning, current or last known GNSSposition fix, etc., just to illustrate a few possible examples.

Continuing with the above discussion, positioning tiles may, forexample, be provided and/or made available to a mobile device via anysuitable technology, such as by a location server or any other suitableserver (e.g., a navigation server, etc.) and/or entity. By way ofexample but not limitation, at times, Zero Power Positioning (ZPP)technology proprietary to Qualcomm® may, for example, be employedherein, in whole or in part. For example, in some instances, one or morepositioning tiles may be provided and/or made available to a mobiledevice via a third party server, such as via one or more communicationlinks and/or upon a request for a location service, as one possibleexample. By way of another example but not limitation, at times,Qualcomm®'s proprietary technology capable of providing one or morepositioning tiles may include, for example, a global terrestrialpositioning (GTP) and/or terrestrial downlink positioning (TDP) protocoland/or approach. Claimed subject matter is not so limited, of course.For example, any other suitable technology and/or approach capable offacilitating and/or supporting timely access to and/or download of oneor more positioning tiles may be utilized, in whole or in part. One ormore positioning tiles may be used, at least in part, by a mobile deviceto obtain estimated locations of one or more observed or “visible”wireless transmitters, such as via corresponding Cell-IDs or otherparameters tagged to respective transmitter locations within the tiles,for example.

Thus, based, at least in part, on its rough location as well aslocations and/or parameters of one or more wireless transmittersobtained via a positioning tile, a mobile device may, for example, becapable of computing a position fix using one or more appropriatetechniques, as discussed above. At times, a mobile device may transmitone or more parameters detected via a scan to a server along with arequest to compute a position fix, such as without requesting and/ordownloading a tile, for example. In response, a server may, for example,transmit one or more messages to a mobile device including a positionfix of the mobile device. In some instances, a response message from aserver may also reveal one or more available tiles that may be used, atleast in part, for obtaining future position fixes within an areaproximate to an estimated location, for example. If desired or otherwiseappropriate, a mobile device may, for example, select to download one ormore revealed tiles and may locally store these or other tiles for usein one or more future positioning operations. It should be noted that“wireless transmitters” and “transmitters” may be used interchangeablyherein, and may be capable of transmitting and/or receiving wirelesssignals, depending on an implementation.

As was also indicated, in some instances, positioning tiles mayfacilitate and/or support positioning for one or more emergencyservices, such as E911 emergency services, for example, dispatching anappropriate first responder (e.g., fire, police, ambulance, etc.) to alocation of a mobile device in response to a 911 emergency calloriginating from the mobile device. Thus, in response to an emergency911 call to a Public Safety Answering Point (PSAP), for example, thePSAP may initiate operations for determining an estimated location of anemergency caller for dispatch of a public safety service. Here, a mobiledevice may, for example, receive from a location server a messagecomprising a location request, such as in response to a detection of anemergency event at a PSAP. In response to this message, a mobile devicemay, for example, initiate an E911 positioning session, such as obtainone or more observations and access and/or download one or morepositioning tiles for computation of a position fix using one or moreappropriate techniques (e.g., trilateration, etc.). In this context,“observation” refers to a measured attribute or characteristic of awireless signal transmitted by a wireless transmitter and acquired by anobserving receiver or other sensor co-located with a mobile device. Insome instances, one or more observations may include, for example, oneor more measurements of times of arrival (TOAs), time differences ofarrival (TDOAs), RSSIs, RTTs, etc. of wireless signals transmitted byproximate wireless transmitters and acquired at a receiver of a mobiledevice, though claimed subject is not so limited. For example, at times,one or more observations may comprise, for example, one or more TOAs ofCDMA pilot measurements in AFLT. Having obtained (e.g., from a mobiledevice, etc.) and/or computed (e.g., on a server, etc.) a position fix,a location server may, for example, communicate the position fix to anappropriate PSAP, such as for dispatching an appropriate first responderto a mobile device's location.

Typically, during an E911 or other positioning session, however, such asinitiated in response to receiving a message indicating an E911emergency or like event (e.g., a location request, etc.), for example, amobile device may primarily rely on parameters of wireless transmitterscontained in one or more provided positioning tiles. Thus, at times, amobile device may, for example, be unable to take additional advantageof one or more parameters comprising observations of wirelesstransmitters obtained prior to an E911 or other positioning session. Forexample, in some instances, a location server may not be aware of anumber of wireless transmitters, such as newly-installed, moved,positioned deeply indoors, etc. within a particular area or a portion ofan area and, as such, their respective parameters may be absent from aprovided positioning tile. A mobile device, while being located in suchan area, may nevertheless observe current signals transmitted from thesetransmitters, but may not be able to correlate their parameters withparameters in positioning assistance data provided via a tile due, atleast in part, to their absence. As such, at times, signals fromwireless transmitters currently observed by a mobile device may be oflimited use in obtaining and/or refining a position fix, such as viatrilateration based on locations of transmitters, for example, or liketechniques. Thus, in some instances, such as if a positioning tile doesnot comprise parameters for a requisite number of currently observedwireless transmitters, for example, obtaining and/or refining asufficiently accurate position fix may not be attainable. Accordingly,it may be desirable to develop one or more methods, systems, and/orapparatuses that may enable or otherwise improve mobile devicelocalization-related services, which may include E911 emergencyservices, such as implemented in connection with one or more positioningtiling approaches, for example.

Thus, as will be described in greater detail below, in animplementation, a mobile device, while traveling within an area ofinterest, indoor or otherwise, may, for example, collect and/or store ina local memory observations of signals transmitted from proximatewireless transmitters, such as in one or more batches of correspondingmeasurements. In some instances, observations may, for example, becollected and/or stored prior to receiving a message initiating anapplicable positioning session, such as a location or position fixrequest, 911 emergency call, positioning tile download, or the like. Aswill also be seen, at times, observations may, for example, be storedbased, at least in part, on one or more associations between theobservations, which may include time-related associations,location-related associations, parameter-related associations, or thelike, or any combination thereof. In response to a request for aposition fix, E911-related or otherwise, a mobile device may, forexample, obtain an applicable positioning tile, as discussed above(e.g., via a GTP, TDP, etc. protocol), and may apply associatedparameters to one or more stored observations to obtain and/or refine aposition fix. For example, a mobile device may retrieve a particularmeasurement batch, or any combination thereof, and may compute aposition fix utilizing past observations from unknown wirelesstransmitters, such as those absent from a provided tile, as a functionof known wireless transmitters observed at the same or similar time,from the same or similar location, having the same or similarparameters, etc., or any combination thereof. Unknown and known wirelesstransmitters will be discussed in greater detail below. As such, attimes, a mobile device may, for example, be capable of computing asufficient position fix even if no parameters of unknown wirelesstransmitters were provided in a positioning tile, which may provebeneficial. In some instances, these or like approaches may reduce oreliminate obtaining additional observations subsequent to a request fora position fix, which may, for example, reduce time to first fix (TTFF),improve power consumption of a mobile device, or the like. At times,stored observations may, for example, be de-weighted as a function ofage, discarded from a memory beyond a certain age, etc., such as tofacilitate and/or support localization via one or more positioningtiles.

FIG. 1 is a schematic diagram illustrating features associated with animplementation of an example operating environment 100 capable offacilitating and/or supporting one or more processes and/or operationsfor enhancing positioning via measurement batching for use in or with amobile device, such as a location-aware mobile device 102, for example.It should be appreciated that operating environment 100 is describedherein as a non-limiting example that may be implemented, in whole or inpart, in the context of various electronic communications networks orcombination of such networks, such as public networks (e.g., theInternet, the World Wide Web), private networks (e.g., intranets), WWAN,wireless local area networks (WLAN, etc.), or the like. It should alsobe noted that claimed subject matter is not limited to indoorimplementations. For example, at times, one or more operations ortechniques described herein may be performed, at least in part, in anindoor-like environment, which may include partially or substantiallyenclosed areas, such as urban canyons, town squares, amphitheaters,parking garages, rooftop gardens, patios, or the like. At times, one ormore operations or techniques described herein may be performed, atleast in part, in an outdoor environment.

As illustrated, in an implementation, mobile device 102 may, forexample, receive or acquire satellite positioning system (SPS) signals104 from SPS satellites 106. In some instances, SPS satellites 106 maybe from a single global navigation satellite system (GNSS), such as theGPS or Galileo satellite systems, for example. In other instances, SPSsatellites 106 may be from multiple GNSS such as, but not limited to,GPS, Galileo, Glonass, or Beidou (Compass) satellite systems. In certainimplementations, SPS satellites 106 may be from any one several regionalnavigation satellite systems (RNSS) such as, for example, WAAS, EGNOS,QZSS, just to name a few examples.

At times, mobile device 102 may, for example, transmit wireless signalsto, or receive wireless signals from, a suitable wireless communicationnetwork. In one example, mobile device 102 may communicate with acellular communication network, such as by transmitting wireless signalsto, or receiving wireless signals from, one or more wirelesstransmitters capable of transmitting and/or receiving wireless signals,such as a base station transceiver 108 over a wireless communicationlink 110, for example. Similarly, mobile device 102 may transmitwireless signals to, or receive wireless signals from a localtransceiver 112 over a wireless communication link 114. Base stationtransceiver 108, local transceiver 112, etc. may be of the same orsimilar type, for example, or may represent different types of devices,such as Wi-Fi access points, radio beacons, cellular base stations,femtocells, or the like, depending on an implementation. Similarly,local transceiver 112 may comprise, for example, a wireless transmitterand/or receiver capable of transmitting and/or receiving wirelesssignals. For example, as will be seen, at times, wireless transceiver112 may be capable of obtaining one or more observations from one ormore other terrestrial transmitters.

In a particular implementation, local transceiver 112 may be capable ofcommunicating with mobile device 102 at a shorter range over wirelesscommunication link 114 than at a range established via base stationtransceiver 108 over wireless communication link 110. For example, localtransceiver 112 may be positioned in an indoor or like environment andmay provide access to a wireless local area network (WLAN, e.g., IEEEStd. 802.11 network, etc.), wireless personal area network (WPAN, e.g.,Bluetooth® network, etc.), or like local area networks. For example, inanother example implementation, local transceiver 112 may comprise afemtocell or picocell capable of facilitating communication via link 114according to an applicable cellular or like wireless communicationprotocol. Of course, it should be understood that these are merelyexamples of networks that may communicate with mobile device 102 over awireless link, and claimed subject matter is not limited in thisrespect. For example, in some instances, operating environment 100 mayinclude a larger number of base station transceivers 108, localtransceivers 112, etc.

In an implementation, base station transceiver 108, local transceiver112, etc. may communicate with servers 116, 118, or 120 over a network122 via one or more links 124. Network 122 may comprise, for example,any combination of wired or wireless communication links. In aparticular implementation, network 122 may comprise, for example,Internet Protocol (IP)-type infrastructure capable of facilitating orsupporting communication between mobile device 102 and one or moreservers 116, 118, 120, etc. via local transceiver 112, base stationtransceiver 108, etc. In another implementation, network 122 maycomprise, for example cellular communication network infrastructure,such as a base station controller or master switching center tofacilitate and/or support mobile cellular communication with mobiledevice 102. As was indicated, in some instances, network 122 mayfacilitate and/or support communications with a PSAP (not shown) or likeentity, such as for purposes of initiating and/or implementing an E911or like positioning session, for example. Servers 116, 118, and/or 120may comprise any suitable servers or combination thereof capable offacilitating and/or supporting one or more operations and/or techniquesdiscussed herein. For example, servers 116, 118, and/or 120 may compriseone or more location servers (e.g., Evolved Serving Mobile LocationServer (E-SMLC), Secure User Plane Location Server/SUPL LocationPlatform (SUPL SLP), etc.), positioning assistance servers, navigationservers, map servers, crowdsourcing servers, network-related servers, orthe like.

In particular implementations, and as also discussed below, mobiledevice 102 may have circuitry or processing resources capable ofdetermining a position fix or estimated location of mobile device 102,rough or otherwise. For example, if satellite signals 104 are available,mobile device 102 may compute a position fix based, at least in part, onpseudorange measurements to four or more SPS satellites 106. Here,mobile device 102 may compute such pseudorange measurements based, atleast in part, on pseudonoise code phase detections in signals 104acquired from four or more SPS satellites 106. In particularimplementations, mobile device 102 may receive from one or more servers116, 118, or 120 positioning assistance data to aid in the acquisitionof signals 104 transmitted by SPS satellites 106 including, for example,almanac, ephemeris data, Doppler search windows, just to name a fewexamples. If satellite signals 104 are unavailable, mobile device 102may, for example, compute a position fix based, at least in part, onCell ID, enhanced Cell ID, or like positioning. As discussed below, insome instances, mobile device 102 may, for example, compute its roughposition based, at least in part, on these or like techniques (e.g.,GNSS positioning, dead reckoning, etc.), such as for purposes ofobtaining one or more positioning tiles, among other things.

In some implementations, mobile device 102 may obtain a position fix byprocessing wireless signals received from one or more terrestrialtransmitters positioned at known locations (e.g., base stationtransceiver 108, local transceiver 112, etc.) using any one of severaltechniques, such as, for example, OTDOA, AFLT, or the like. In thesetechniques, a range from mobile device 102 may, for example, be measuredto three or more of terrestrial transmitters based, at least in part, onone or more reference signals transmitted by these transmitters andreceived at mobile device 102. Here, servers 116, 118, or 120 may becapable of providing positioning assistance data to mobile device 102including, for example, locations, identities, etc. of terrestrialtransmitters to facilitate and/or support one or more applicablepositioning techniques. At times, servers 116, 118, or 120 may include,for example, a base station almanac (BSA) indicating locations,identities, etc. of cellular base stations (e.g., base stationtransceiver 108, local transceiver 112, etc.) in one or more particularareas or regions associated with operating environment 100.

As alluded to previously, in particular environments, such as indoor orlike environments (e.g., urban canyons, etc.), mobile device 102 may notbe capable of acquiring or processing signals 104 from a sufficientnumber of SPS satellites 106 so as to perform a suitable positioningtechnique. Thus, optionally or alternatively, mobile device 102 may becapable of determining a position fix based, at least in part, onsignals acquired from one or more local transmitters 112, such asfemtocells, Wi-Fi access points, or the like. For example, mobile device102 may obtain a position fix by measuring ranges to three or more localtransceivers 112 positioned at known locations. In some implementations,mobile device 102 may, for example, measure ranges by obtaining a MACaddress from local transceiver 112, as was also discussed.

In an implementation, mobile device 102 may, for example, receivepositioning assistance data for one or more positioning operations fromservers 116, 118, and/or 120. As was indicated, at times, positioningassistance data may include, for example, locations, identities, etc. ofone or more local transceivers 112, base station transceivers 108, etc.positioned at known locations for measuring ranges to thesetransmitters. In some instances, positioning assistance data mayinclude, for example, radio heat maps, context parameter maps,routeability graphs, positioning tiles, etc., just to name a fewexamples. Other assistance data may include, for example, electronicdigital maps of indoor or like areas for display or to aid innavigation. A map may be provided to mobile device 102 as it enters aparticular area, for example, and may show applicable features such asdoors, hallways, entry ways, walls, etc., points of interest, such asbathrooms, pay phones, room names, stores, or the like. By obtaining adigital map of an indoor or like area of interest, mobile device 102may, for example, be capable of overlaying its current location over thedisplayed map of the area so as to provide an associated user withadditional context, frame of reference, or the like. The terms“positioning assistance data” and “navigation assistance data” may beused interchangeably herein.

According to an implementation, mobile device 102 may access navigationassistance data via servers 116, 118, and/or 120 by, for example,requesting such data through selection of a universal resource locator(URL). In particular implementations, servers 116, 118, and/or 120 maybe capable of providing navigation assistance data to cover manydifferent areas including, for example, floors of buildings, wings ofhospitals, terminals at an airport, portions of a university campus,areas of a large shopping mall, etc., just to name a few examples. Also,if a memory or data transmission resources at mobile device 102 makereceipt of positioning assistance data for all areas served by servers116, 118, and/or 120 impractical or infeasible, a request for such datafrom mobile device 102 may, for example, indicate a rough or courseestimate of a location of mobile device 102. Mobile device 102 may thenbe provided navigation assistance data covering, for example, one ormore areas including or proximate to a roughly estimated location ofmobile device 102. In some instances, one or more servers 116, 118,and/or 120 may facilitate and/or support providing one or morepositioning tiles, such as for determining a position fix in connectionwith an E911 positioning session, for example, and may provide theposition fix to an applicable PSAP via network 122, as was alsoindicated.

Even though a certain number of computing platforms and/or devices areillustrated herein, any number of suitable computing platforms and/ordevices may be implemented to facilitate and/or support one or moretechniques or processes associated with operating environment 100. Forexample, at times, network 122 may be coupled to one or more wired orwireless communication networks (e.g., WLAN, etc.) so as to enhance acoverage area for communications with mobile device 102, one or morebase station transceivers 108, local transceiver 112, servers 116, 118,120, or the like. In some instances, network 122 may facilitate and/orsupport femtocell-based operative regions of coverage, for example.Again, these are merely example implementations, and claimed subjectmatter is not limited in this regard.

With this in mind, attention is now drawn to FIG. 2, which is a flowdiagram illustrating an implementation of an example process 200 thatmay be performed, in whole or in part, to facilitate and/or support oneor more operations and/or techniques for enhancing positioning viameasurement batching. As was indicated, at times, process 200 may beimplemented, at least in part, via a location-aware mobile device, suchas, for example, mobile device 102 of FIG. 1, though claimed subjectmatter is not so limited. For example, in some instances, one or moreoperations of process 200 may be implemented, at least in part, via aserver device, such as one or more servers 116, 118, and/or 120 of FIG.1, or any combination of a server device and a mobile device. It shouldbe noted that information acquired or produced, such as, for example,input signals, output signals, operations, results, etc. associated withexample process 200 may be represented via one or more digital signals.It should also be appreciated that even though one or more operationsare illustrated or described concurrently or with respect to a certainsequence, other sequences or concurrent operations may be employed. Inaddition, although the description below references particular aspectsor features illustrated in certain other figures, one or more operationsmay be performed with other aspects or features.

Example process 200 may, for example, begin at operation 202 withstoring, at a mobile device, observations of radio frequency (RF)signals transmitted from one or more wireless transmitters in an area,the observation being stored based, at least in part, on one or moreassociations between the observations. Observations may, for example, becollected and/or stored via a suitable host application or like process,such as a background process, as one possible example, dedicated orotherwise. A host application or like process may, for example, beprovided to a user's mobile device by a suitable server, stored locallyon a mobile device, etc. An application or like process may, forexample, be activated, launched, downloaded, etc. upon user's turningon, rebooting, or activating a mobile device, entering an area ofinterest, upon request, user input, or the like. Thus, a mobile device,while traveling within an area of interest, indoor or otherwise, may,for example, observe, such as receive and/or acquire in connection witha scan (e.g., active, passive, etc.), for example, wireless signals fromone or more proximate or “visible” wireless transmitters, such as one ormore cellular base stations, Wi-Fi access points, Bluetooth® beacons,etc., or any combination thereof. In some instances, a mobile devicemay, for example, obtain and/or store one or more measurementsoriginating from one or more on-board sensors, such as instead of or inaddition to performing a scan. Sensor measurements may, for example, beassociated and/or stored with signal observations, if appropriate and/orapplicable, with reference to and/or based, at least in part, on a timeof measurement sensing and/or signal observing, a particular locationwithin an area, a particular type of a measurement (e.g., acceleration,etc.), or the like. On-board sensors may comprise, for example, one ormore inertial sensors (e.g., accelerometers, gyroscopes, compasses,magnetometers, gravitometers, etc.), ambient environment sensors (e.g.,ambient light detectors, radio frequency (RF) sensors, proximitysensors, piezo sensors, capacitance and/or resistance-based touchsensors, vibrational sensors, thermometers, etc.), or other sensorscapable of measuring various states of a mobile device. These or likesensor measurements may, for example, be used, at least in part, toestimate locations of one or more wireless transmitters in an area ofinterest in a fashion similar to one or more approaches discussed herein(e.g., via correlating barometric pressure measurements of applicablewireless transmitters, etc.).

Having acquired wireless signals, a mobile device may, for example,decode particular parameters encoded in the wireless signals using oneor more appropriate techniques. In some instances, parameters maycomprise, for example, identities (e.g., Cell IDs, MAC addresses, etc.)of observed wireless transmitters as well as received signalstrength-related measurements (e.g., RSSI, etc.), round-trip delaytimes-related measurements (e.g., RTT, etc.), or the like. Claimedsubject matter is not limited to these particular measurements, ofcourse. Any suitable measurements capable of facilitating and/orsupporting obtaining a position fix of a mobile device via anyappropriate technique may be used herein, in whole or in part, orotherwise considered. At times, observations may comprise, for example,observations obtained from one or more unknown wireless transmitters. Inthis context, “unknown” wireless transmitters refer to wirelesstransmitters locations and/or identities of which may not be known to amobile device, such as at the time of observing and/or storingrespective observations, for example, in the absence of applicablepositioning assistance data, such as one or more parameters comprising apositioning tile covering a relevant area, as one possible example.

Continuing with the above discussion, a mobile device may, thus, storesignal observations in a local memory, such as prior to a positioningsession initiated via a location request or like event (e.g., a 911emergency call, positioning tile download, etc.), for example. A mobiledevice may, for example, store observations in any suitable manner, suchas in one or more measurements batches based, at least in part, on oneor more associations between such observations, which may includetime-related associations, location-related associations,parameter-related associations, or the like, or any combination thereof.For example, as illustrated in FIG. 3, in at least one implementation,observations may be time stamped, such as with a time and/or date atwhich signals were observed, and may be stored in batches of particularmeasurements (e.g., Wi-Fi, Bluetooth®, cellular, inertial, barometric,pedestrian dead reckoning, etc. sensor, etc.), illustrated generally as302 through N. As also seen, at times, batches may, for example, bestored with reference to suitable time periods, illustrated generally ast₀-t₁, t₁-t₂, and so forth until a time t_(n), which may correspond to a911 call or like event (e.g., a location request, etc.) that mayinitiate a positioning session. Here, a time period may be determined,at least in part, experimentally and may be set, pre-defined, and/orconfigured (e.g., by a user, wireless service provider, etc.), forexample, or otherwise dynamically defined in some manner depending on aparticular environment, application, area, emergency and/or wirelessservice, mobile device, or the like. Thus, a time period may comprise aconfigurable parameter that may be based, at least in part, on usermobility, rate at which wireless scans are made, maximum allowed storagecapacity, maximum number of observed wireless transmitters, maximumnumber of observed that can be stored, or the like. By way of examplebut not limitation, in one particular simulation or experiment, itappeared that a time period in a range between 100.0 seconds (e.g., fora faster-moving user) and 300.0 seconds (e.g., for a slower-moving user)may prove beneficial for enhancing positioning via measurement batching,including E911 or like positioning. Of course, details relating to atime period and/or particular measurements are intended as merelyexamples to which claimed subject matter is not limited.

Thus, as seen, in at least one implementation, observations may beassociated or “linked” together, such as for storing in a suitable localmemory via a number of measurement batches (e.g., in a buffer, etc.),for example, based, at least in part, on a time and/or date of theobservations and/or with reference to one or more suitable time periods.As discussed below, these or like associations (e.g., location-related,parameter-related, etc.) may, for example, facilitate and/or supportestimating locations of one or more currently observed wirelesstransmitters absent from provided positioning assistance data, such as apositioning tile. Namely, using one or more measurement batches and withthe knowledge of locations of wireless transmitters obtained from aprovided positioning tile, a mobile device may, for example, be capableof estimating locations of one or more unknown (e.g., absent from thetile, etc.) yet currently observed wireless transmitters as a functionof past observations of known wireless transmitters. For example, insome instances, a location of one or more currently observed but unknownwireless transmitters comprising a particular stored measurement batchmay be assumed to be associated or “linked with”—and, thus, proximateto—a location of one or more known wireless transmitters in the batchthat were previously observed at the same time, as discussed below.

It should be noted that claimed subject matter is not limited to aparticular association and/or assumption, of course. For example, as wasindicated, in some instances, observations may be stored in measurementbatches based, at least in part, on location-related associations,meaning that observations may be associated or “linked” together in aparticular batch with reference to a particular location from whichwireless signals were observed, such as in a similar fashion. Here, if amobile device, while at a particular location within an indoor or likearea of interest, observes signals from a number of wirelesstransmitters, for example, and subsequently visits the same location inthe area or a location proximate to the area, these wirelesstransmitters, of transmitters observed from that or proximate location,may be linked or associated together, such as in a similar fashion viaan appropriate measurement batch. As was also indicated, a times,observations may, for example, be stored in measurement batches based,at least in part, on parameter-related associations, meaning thatobservations may be associated or “linked” together in a particularbatch with reference to one or more particular parameters that wereobserved (e.g., RSSI, RTT, etc.) from a particular location, as was alsoindicated. For this implementation, a mobile device, while travelingwithin an indoor or like area of interest, may link together wirelesstransmitters exhibiting the same or similar signaling (e.g., RSSI, etc.)or timing (e.g., RTT, etc.) characteristics in a similar fashion, but,at times, may limit batching to transmitters with a higher qualitymeasurements (e.g., stronger signal strength, etc.) and/or invariantsignal delays, for example.

In at least one implementation, observations may also be geo-tagged in asuitable manner, such as with appropriate geographic (e.g., latitude,longitude, etc.) or local coordinates, for example, while beingcollected and/or stored in one or more measurement batches. Here, amobile device, such as while traveling within an area in which SPSsignals may be reliably received or acquired, may, for example,correlate or associate locations of one or more currently observedproximate wireless transmitters with a current position fix obtained viaan SPS, if applicable or available. In some instances, such as inSPS-denied environments (e.g., deep indoors, etc.), for example, a lastknown position fix obtained via an SPS may also be used, at least inpart, to approximate and/or geo-tag locations of observed wirelesstransmitters, such as in connection with one or more dead reckoning orlike techniques. For example, here, a mobile device may utilize one ormore on-board sensors, such as an inertial sensor to estimate locationsof observed wireless transmitters via incrementing a last known positionfix using a known direction of travel and/or estimated speed over someknown elapsed time. Of course, these are merely details to which claimedsubject matter is not limited. For example, any other suitable sensor orcombination of sensors may be utilized, at least in part, to estimateand/or geo-tag locations of one or more observed wireless transmitters.In addition, any other suitable approaches, such as Cell-ID positioning,Enhanced Cell-ID positioning, or the like may be also used, in whole orin part, to approximate and/or geo-tag locations of observed wirelesstransmitters.

According to an implementation, to facilitate and/or supportlocalization via one or more positioning tiles, stored observations ofRF signals may, for example, be de-weighted as a function of age,discarded from a local memory beyond a certain age, as was indicated. Asan example of an age-type weighting, a particular characteristic (e.g.,RSSI, RTT, etc.) of a wireless transmitter may, for example, be weightedby a factor that is inversely proportional to an expected distancetraveled by a user in a measurement age or interval. For example, ifthere are three wireless transmitters, two of which are seen with a timelag of zero seconds at the time of positioning, and the thirdmeasurement is 10.0 seconds old and a user's speed is 5.0 meters persecond, then that particular wireless transmitter may be de-weighted bya function of age as, for example, K/(10*5)̂2, where K is a constant thatmay be determined experimentally and/or dynamically based, at least inpart, on an associated wireless environment, mobile device, application,positioning protocol, etc., or any combination thereof. Claimed subjectmatter is not limited to these particular details, of course.

Referring back to example process 200 of FIG. 2, with regard tooperation 204, the observations may, for example, be processed in somemanner, such as to obtain an estimate of a location of the mobile devicebased, at least in part, on the associations and responsive to a requestfor the estimate occurring subsequent to the storing of theobservations. For example, in response to initiation of a positioningsession, such as triggered via a 911 call, location request, etc.subsequent to storing of observations (e.g., at a time t_(n) of FIG. 3,etc.), a mobile device may obtain a relevant positioning tile, such asdiscussed above, and may access its local memory to retrieve one or moreappropriate batches of stored observations in a suitable manner. Morespecifically, in an implementation, a mobile device may, for example,retrieve a particular measurement batch of stored observations viacorrelating one or more parameters of wireless transmitters containedwithin a provided positioning tile with one or more stored parameters ofwireless transmitters within the batch. As a way of illustration, usingexample implementation of FIG. 3, a mobile device may, for example,retrieve batch 304 if MAC addresses, RSSIs, RTTs, etc. of one or morewireless transmitters comprising this particular batch correspond to MACaddresses, RSSIs, RTTs, etc. of one or more wireless transmitterscontained in a provided positioning tile. Claimed subject matter is notso limited, of course.

Continuing with the above discussion, by way of another example, amobile device may, for example, retrieve batch 302 if a time periodt₀-t₁ is within a certain time threshold from a time of initiation of anapplicable positioning session (e.g., an E911 positioning session,etc.), such as from a time t_(n). Such a threshold may also bedetermined, at least in part, experimentally and may be set,pre-defined, and/or configured (e.g., by a user, wireless serviceprovider, etc.), for example, or otherwise dynamically defined in somemanner depending on a particular environment, application, area,emergency and/or wireless service, mobile device, or the like. By way ofexample but not limitation, in one particular simulation or experiment,it has been observed that a time threshold between 15.0 and 30.0 minutesprior to a time of initiation of a positioning session may provebeneficial for retrieving a measurement batch, for an E911 positioningsession or otherwise. A time threshold may also account for a user'smobility, maximum storage capacity, etc., such as discussed above.Claimed subject matter is not limited to these particular examples, ofcourse. In some instances, all or most stored measurement batches ofpast observations may, for example, be accessed and/or retrieved, suchas to facilitate and/or support computing a position fix.

Continuing with operation 204 of FIG. 2, in an implementation, havingretrieved an applicable batch of measurements, a mobile device may, forexample, process observations within the batch so as to estimatelocations of one or more currently observed but unknown wirelesstransmitters, such as those absent from a provided positioning tile, aswas indicated. For example, at times, locations of one or more currentlyobserved unknown wireless transmitters may be estimated as a function ofpast observations of known wireless transmitters associated or “linked”together with the unknown wireless transmitters via a particular batch.More specifically, in certain simulations or experiments, it has beenobserved that locations of one or more currently observed but unknownwireless transmitters comprising a particular stored measurement batchmay be assumed to be proximate to locations of one or more knownwireless transmitters within the batch, such as those that werepreviously observed at the same time, for example. Thus, in someinstances, locations of one or more known (e.g., via a tile, etc.)wireless transmitters within a particular batch may, for example, beused as “proxy” locations of one or more unknown wireless transmitterscomprising the same batch, such as for purposes of computing a positionfix. Here, any suitable approaches, statistical or otherwise, capable ofapproximating unknown transmitter locations may be used, in whole or inpart, or otherwise considered. For example, at times, a weightingapproach emphasizing contribution of one or more stored observations ofknown wireless transmitters within a particular measurement batch toaffect location estimations of one or more unknown wireless transmittersin the batch may, for example, be employed, in whole or in part. In someinstances, a weighting approach may also account for a number offactors, such as wireless transmitter location uncertainty, observationuncertainty, observation age, signal characteristic (e.g., RSSI, RTT,etc.), user's mobility, etc., or any combination thereof. Of course,details relating to particular assumptions, observations, and/orapproaches are intended as merely examples to which claimed subjectmatter is not limited. It should be appreciated that any of a variety ofpossible other approaches, statistical or otherwise, may be utilized toestimate unknown transmitter locations, such as, for example, a median,a mean, a mode, a percentile of mean, a number of instances, a ratio, arate, a frequency, an entropy, mutual information, a division, adifference, etc., or any combination thereof.

In some instances, a mobile device may, for example, be capable ofestimating locations of one or more currently observed but unknownwireless transmitters using their stored geo-tagged locations, such asin a similar fashion (e.g., as a function of known wirelesstransmitters, etc.). For example, a mobile device may correlategeo-tagged locations of one or more known wireless transmitters providedvia a positioning tile, if applicable or available, with storedgeo-tagged locations of one or more unknown wireless transmitters, suchas approximated as a mobile device's location at the time of respectiveobservations. Here a mobile device may, for example, use locations ofone or more known wireless transmitters in a particular batch as proxiesfor locations of one or more unknown wireless transmitters in the batch,such as via an assumption that these may be located in a sufficientlyclose geographic proximity since their signals were observed at the sametime. At times, to approximate unknown transmitter locations, a mobiledevice may, for example utilize a suitable proximity threshold that mayaccount, for example, for a Euclidean distance between geo-coordinatesof appropriate wireless transmitters, just to illustrate one possibleimplementation. Likewise, a proximity threshold may be determined, atleast in part, experimentally and may be set, pre-defined, and/orconfigured (e.g., by a user, wireless service provider, etc.), forexample, or otherwise dynamically defined in some manner depending on aparticular environment, application, area, emergency and/or wirelessservice, mobile device, or the like. By way of example but notlimitation, in one particular simulation or experiment, it has beenobserved that a proximity threshold between 5.0 and 10.0 meters mayprove beneficial. Claimed subject matter is not limited to a particularapproach, metric, and/or threshold, of course. Any other suitableproximity determination approaches, metrics, and/or thresholds may beused herein, in whole or in part, or otherwise considered.

According to an implementation, having estimated locations of one ormore unknown but currently observed wireless transmitters, a mobiledevice may, for example, compute its position fix using one or moreappropriate techniques. For example, at times, a position fix of amobile device may be computed via trilateration based, at least in part,on locations of applicable wireless transmitters, such as determined viaone or more approaches discussed above. In some instances, a positionfix may, for example, be determined in connection with an observed timedifference of arrival (OTDOA) technique in which a mobile device mayemploy one or more TOA or TDOA measurements from two or more pairs ofapplicable wireless transmitters, just to illustrate another possibleimplementation. Again, these or like positioning techniques aregenerally known and need not be described here in greater detail. Thus,utilizing one or more approaches discussed herein, a mobile device may,for example, be capable of computing a sufficient position fix even ifno parameters of unknown wireless transmitters were provided in apositioning tile, which may prove beneficial, as was indicated. Attimes, a computed position fix and/or estimated locations of one or morepreviously unknown (e.g., to a server, etc.) wireless transmitters may,for example, be provided to a location or other suitable server via anappropriate message, such as for purposes of updating one or moreapplicable positioning tiles, facilitating and/or supporting E911 orlike positioning, or the like, as was also discussed.

Attention is now drawn to FIG. 4, which is a flow diagram illustratingan implementation of another example process, referenced herein at 400,that may be performed, in whole or in part, to facilitate and/or supportone or more operations and/or techniques for enhancing positioning viameasurement batching for use in or with a location-aware mobile device,such as mobile device 102 of FIG. 1, for example. Likewise, it should benoted that information acquired or produced, such as, for example, inputsignals, output signals, operations, results, etc. associated withexample process 400 may be represented via one or more digital signals.It should also be appreciated that even though one or more operationsare illustrated or described concurrently or with respect to a certainsequence, other sequences or concurrent operations may be employed. Inaddition, although the description below references particular aspectsor features illustrated in certain other figures, one or more operationsmay be performed with other aspects or features.

Example process 400 may, for example, begin at operation 402 withbatching multiple observations of radio frequency (RF) signalstransmitted from a plurality of unknown wireless transmitters in anarea, the multiple observations being obtained while the mobile deviceis positioned at multiple different locations within the area, such asimplemented via one or more operations and/or techniques discussedherein. With regard to operation 404, at least locations of at leastsome of the unknown wireless transmitters in the area may, for example,be obtained, such as via positioning assistance data, as one possibleexample, the locations being obtained subsequently to the batching themultiple observations, such as also implemented via one or moreoperations and/or techniques discussed herein. At operation 406, alocation of at least one wireless transmitter absent from thepositioning assistance data may, for example, be estimated based, atleast in part, on the subsequently obtained locations and the batchedmultiple observations, such as further implemented via one or moreoperations and/or techniques discussed herein.

FIG. 5 is a schematic diagram of an implementation of an examplecomputing environment associated with a mobile device that may be used,at least in part, to facilitate and/or support one or more operationsand/or techniques for enhancing positioning via measurement batching. Anexample computing environment may comprise, for example, a mobile device500 that may include one or more features or aspects of mobile device102 of FIG. 1, though claimed subject matter is not so limited. Forexample, in some instances, mobile device 500 may comprise a wirelesstransceiver 502 capable of transmitting and/or receiving wirelesssignals, referenced generally at 504, such as via an antenna 506 over asuitable wireless communications network. Wireless transceiver 502 may,for example, be capable of sending or receiving one or more suitablecommunications, such as with reference to FIGS. 1-4. Wirelesstransceiver 502 may, for example, be coupled or connected to a bus 508via a wireless transceiver bus interface 510. Depending on animplementation, at times, wireless transceiver bus interface 510 may,for example, be at least partially integrated with wireless transceiver502. Some implementations may include multiple wireless transceivers 502or antennas 506 so as to enable transmitting or receiving signalsaccording to a corresponding multiple wireless communication standardssuch as WLAN or WiFi, Code Division Multiple Access (CDMA),Wideband-CDMA (W-CDMA), Long Term Evolution (LTE), Bluetooth®, just toname a few examples.

In an implementation, mobile device 500 may, for example, comprise anSPS or like receiver 512 capable of receiving or acquiring one or moreSPS or other suitable wireless signals 514, such as via an SPS or likeantenna 516. SPS receiver 512 may process, in whole or in part, one ormore acquired SPS signals 514 for estimating a location of mobile device500, rough or otherwise. In some instances, one or moregeneral-purpose/application processors 518 (henceforth referred to as“processor”), memory 520, digital signal processor(s) (DSP) 522, or likespecialized devices or processors not shown may be utilized to processacquired SPS signals 514, in whole or in part, calculate a location ofmobile device 500, such as in conjunction with SPS receiver 512, or thelike. Storage of SPS or other signals for implementing one or morepositioning operations, such as in connection with one or moreoperations and/or techniques for improving OTDOA positioning via one ormore local wireless transmitters, for example, may be performed, atleast in part, in memory 520, suitable registers and/or buffers (notshown). Although not shown, it should be appreciated that in at leastone implementation one or more processors 518, memory 520, DSPs 522, orlike specialized devices or processors may comprise one or moreprocessing modules capable of storing observations of radio frequency(RF) signals transmitted from one or more wireless transmitters in anarea, the observations being stored based, at least in part, on one ormore associations between the observations; and processing theobservations to obtain an estimate of a location of mobile device 500based, at least in part, on the one or more associations and responsiveto a request for the estimate occurring subsequent to the storing theobservations.

It should be noted that all or part of one or more processing modulesmay be implemented using or otherwise including hardware, firmware,software, or any combination thereof. Processing modules may berepresentative of one or more circuits capable of performing at least aportion of information computing technique or process. By way of examplebut not limitation, processor 518 or DSP 522 may include one or moreprocessors, controllers, microprocessors, microcontrollers, applicationspecific integrated circuits, digital signal processors, programmablelogic devices, field programmable gate arrays, central processing units,graphics processor units, or the like, or any combination thereof. Thus,at times, processor 518 or DSP 522 or any combination thereof maycomprise or be representative of means for means for storingobservations of radio frequency (RF) signals transmitted from one ormore wireless transmitters in an area, the observations being storedbased, at least in part, on one or more associations between theobservations, such as to implement operation 202 of FIG. 2, at least inpart. In addition, in at least one implementation, processor 518 or DSP522 may be representative of or comprise, for example, means forprocessing the observations to obtain an estimate of a location ofmobile device 500 based, at least in part, on the one or moreassociations and responsive to a request for the estimate occurringsubsequent to the storing the observations, such as to implementoperation 204 of FIG. 2, at least in part. Also, in at least oneimplementation, processor 518 or DSP 522 may be representative of orcomprise, for example, means for accessing the local memory to retrieveat least one of the one or more measurement batches via correlating theobservations with one or more subsequent observations of the one or morewireless transmitters in the area, such as to implement operation 204 ofFIG. 2, at least in part.

Further, processor 518 or DSP 522 or any combination thereof maycomprise or be representative of means for batching, at mobile device500, multiple observations of RF signals transmitted from a plurality ofunknown wireless transmitters in an area, the multiple observationsbeing obtained while mobile device 500 is positioned at multipledifferent locations within the area, such as to implement operation 402of FIG. 4, at least in part. In addition, in at least oneimplementation, processor 518 or DSP 522 may be representative of orcomprise, for example, means for obtaining, via positioning assistancedata, at least locations of at least some of the unknown wirelesstransmitters in the area, the locations being obtained subsequently tothe batching the multiple observations, such as to implement operation404 of FIG. 4, at least in part. Also, in at least one implementation,processor 518 or DSP 522 may be representative of or comprise, forexample, means for estimating a location of at least one wirelesstransmitter absent from the positioning assistance data based, at leastin part, on the subsequently obtained locations and the batched multipleobservations, such as to implement operation 406 of FIG. 2, at least inpart.

As illustrated, DSP 522 may be coupled or connected to processor 518 andmemory 520 via bus 508. Although not shown, in some instances, bus 508may comprise one or more bus interfaces that may be integrated with oneor more applicable components of mobile device 500, such as DSP 522,processor 518, memory 520, or the like. In various embodiments, one ormore operations or functions described herein may be performed inresponse to execution of one or more machine-readable instructionsstored in memory 520, such as on a computer-readable storage medium,such as RAM, ROM, FLASH, disc drive, etc., just to name a few examples.Instructions may, for example, be executable via processor 518, one ormore specialized processors not shown, DSP 522, or the like. Memory 520may comprise a non-transitory processor-readable memory,computer-readable memory, etc. that may store software code (e.g.,programming code, instructions, etc.) that may be executable byprocessor 518, DSP 522, or the like to perform operations or functionsdescribed herein.

Mobile device 500 may comprise a user interface 524, which may includeany one of several devices such as, for example, a speaker, microphone,display device, vibration device, keyboard, touch screen, etc., just toname a few examples. In at least one implementation, user interface 524may enable a user to interact with one or more applications hosted onmobile device 500. For example, one or more devices of user interface524 may store analog or digital signals on memory 520 to be furtherprocessed by DSP 522, processor 518, etc. in response to input or actionfrom a user. Similarly, one or more applications hosted on mobile device500 may store analog or digital signals in memory 520 to present anoutput signal to a user. In some implementations, mobile device 500 mayoptionally include a dedicated audio input/output (I/O) device 526comprising, for example, a dedicated speaker, microphone, digital toanalog circuitry, analog to digital circuitry, amplifiers, gain control,or the like. It should be understood, however, that this is merely anexample of how audio I/O device 526 may be implemented, and that claimedsubject matter is not limited in this respect. As seen, mobile device500 may comprise one or more touch sensors 528 responsive to touching orlike pressure applied on a keyboard, touch screen, or the like.

Mobile device 500 may comprise one or more sensors 534 coupled orconnected to bus 508, such as, for example, one or more inertialsensors, ambient environment sensors, or the like. Inertial sensors ofsensors 544 may comprise, for example, one or more accelerometers (e.g.,collectively responding to acceleration of mobile device 500 in one,two, or three dimensions, etc.), gyroscopes or magnetometers (e.g., tosupport one or more compass or like applications, etc.), etc., just toillustrate a few examples. Ambient environment sensors of mobile device500 may comprise, for example, one or more barometric pressure sensors,temperature sensors, ambient light detectors, camera sensors,microphones, etc., just to name few examples. Sensors 534 may generateanalog or digital signals that may be stored in memory 520 and may beprocessed by DSP 522, processor 518, etc., such as in support of one ormore applications directed to positioning or navigation operations,wireless communications, radio heat map learning, video gaming or thelike.

In a particular implementation, mobile device 500 may comprise, forexample, a modem processor 536, dedicated or otherwise, capable ofperforming baseband processing of signals received or downconverted viawireless transceiver 502, SPS receiver 512, or the like. Similarly,modem processor 536 may perform baseband processing of signals to beupconverted for transmission via wireless transceiver 502, for example.In alternative implementations, instead of having a dedicated modemprocessor, baseband processing may be performed, at least in part, byprocessor 518, DSP 522, or the like. In addition, in some instances, aninterface 538, although illustrated as a separate component, may beintegrated, in whole or in part, with one or more applicable componentsof mobile device 500, such as bus 508 or SPS receiver 512, for example.Optionally or alternatively, SPS receiver 512 may be coupled orconnected to bus 508 directly. It should be understood, however, thatthese are merely examples of components or structures that may performbaseband processing, and that claimed subject matter is not limited inthis regard.

FIG. 6 is a schematic diagram illustrating an implementation of anexample computing environment or system 600 that may be associated withand/or include one or more servers and/or other devices capable ofpartially and/or substantially implementing and/or supporting one ormore operations and/or techniques for enhancing positioning viameasurement batching, such as discussed above in connection with FIGS.1-5, for example. Computing environment 600 may include, for example, afirst device 602, a second device 604, a third device 606, etc., whichmay be operatively coupled together via a communications network 608. Insome instances, first device 602 may comprise a location server capableof providing positioning assistance data and/or associated parameters,such as, for example, identities, locations, etc. of wirelesstransmitters, radio heat map, base station almanac, database of wirelesstransmitters, bias estimates, signal measurements, reference transmitterparameters, neighbor transmitter parameters, positioning tiles, neighborlists, or the like, such as discussed herein. For example, first device602 may also comprise a server capable of providing an electronicdigital map to a mobile device based, at least in part, on a roughestimate of a location of the mobile device (e.g., determined via lastknown SPS position fix, dead reckoning using one or more appropriatesensors, Cell ID, enhanced Cell ID, positioning tiles, etc.), uponrequest, or the like. First device 602 may also comprise a servercapable of providing any other suitable positioning assistance data(e.g., a radio heat map, positioning tiles, etc.) relevant to a locationof a mobile device, such as in a similar fashion. Second device 604 orthird device 606 may comprise, for example, mobile devices, thoughclaimed subject matter is not so limited. For example, in someinstances, second device 604 may comprise a server functionally orstructurally similar to first device 602, just to illustrate anotherpossible implementation. In addition, communications network 608 maycomprise, for example, one or more wireless transmitters, such ascellular base stations, Wi-Fi access points, femtocells, or the like. Ofcourse, claimed subject matter is not limited in scope in theserespects.

First device 602, second device 604, or third device 606 may berepresentative of any device, appliance, platform, or machine that maybe capable of exchanging parameters and/or information overcommunications network 608. By way of example but not limitation, any offirst device 602, second device 604, or third device 606 may include:one or more computing devices or platforms, such as, for example, adesktop computer, a laptop computer, a workstation, a server device, orthe like; one or more personal computing or communication devices orappliances, such as, for example, a personal digital assistant, mobilecommunication device, or the like; a computing system or associatedservice provider capability, such as, for example, a database orinformation storage service provider/system, a network serviceprovider/system, an Internet or intranet service provider/system, aportal or search engine service provider/system, a wirelesscommunication service provider/system; or any combination thereof. Anyof first, second, or third devices 602, 604, and 606, respectively, maycomprise one or more of a mobile device, wireless transmitter orreceiver, server, etc. in accordance with example implementationsdescribed herein.

In an implementation, communications network 608 may be representativeof one or more communication links, processes, or resources capable ofsupporting an exchange of information between at least two of firstdevice 602, second device 604, or third device 606. By way of examplebut not limitation, communications network 608 may include wireless orwired communication links, telephone or telecommunications systems,information buses or channels, optical fibers, terrestrial or spacevehicle resources, local area networks, wide area networks, intranets,the Internet, routers or switches, and the like, or any combinationthereof. As illustrated, for example, via a dashed lined box partiallyobscured by third device 606, there may be additional like devicesoperatively coupled to communications network 608. It is also recognizedthat all or part of various devices or networks shown in computingenvironment 600, or processes or methods, as described herein, may beimplemented using or otherwise including hardware, firmware, software,or any combination thereof.

By way of example but not limitation, second device 604 may include atleast one processing unit 610 that may be operatively coupled to amemory 612 via a bus 614. Processing unit 610 may be representative ofone or more circuits capable of performing at least a portion of asuitable computing procedure or process. For example, processing unit610 may include one or more processors, controllers, microprocessors,microcontrollers, application specific integrated circuits, digitalsignal processors, programmable logic devices, field programmable gatearrays, or the like, or any combination thereof. Although not shown,second device 604 may include a location-tracking unit that may initiatea position fix of a suitable mobile device, such as in an area ofinterest, for example, based, at least in part, on one or more receivedor acquired wireless signals, such as from an SPS, one or more cellularbase stations, Wi-Fi access points, etc. In some implementations, alocation-tracking unit may be at least partially integrated with asuitable processing unit, such as processing unit 610, for example,though claimed subject matter is not so limited. In certain server-basedor server-supported implementations, processing unit 610 may, forexample, comprise means for storing observations of radio frequency (RF)signals transmitted from one or more wireless transmitters in an area,the observations being stored based, at least in part, on one or moreassociations between the observations, such as to facilitate and/orsupport operations 202 and/or 204 of FIG. 2, at least in part. In someinstances, processing unit 610 may, for example, comprise means forprocessing the observations to obtain an estimate of a location of amobile device based, at least in part, on the one or more associationsand responsive to a request for the estimate occurring subsequent to thestoring the observations, such as to facilitate and/or supportoperations 202 and/or 204 of FIG. 2, at least in part. At times,processing unit 610 may, for example, comprise means for accessing thelocal memory to retrieve at least one of the one or more measurementbatches via correlating the observations with one or more subsequentobservations of the one or more wireless transmitters in the area, suchas to facilitate and/or support operations 202 and/or 204 of FIG. 2, atleast in part.

Further, in certain server-based or server-supported implementations,processing unit 610 may, for example, comprise means for batching, at amobile device, multiple observations of RF signals transmitted from aplurality of unknown wireless transmitters in an area, the multipleobservations being obtained while the mobile device is positioned atmultiple different locations within the area, such as to facilitateand/or support operations 402, 404, and/or 406 of FIG. 4, at least inpart. In some instances, processing unit 610 may, for example, comprisemeans for obtaining, via positioning assistance data, at least locationsof at least some of the unknown wireless transmitters in the area, thelocations being obtained subsequently to the batching the multipleobservations, such as to facilitate and/or support operations 402, 404,and/or 406 of FIG. 4, at least in part. At times, processing unit 610may, for example, comprise means for estimating a location of at leastone wireless transmitter absent from the positioning assistance databased, at least in part, on the subsequently obtained locations and thebatched multiple observations, such as to facilitate and/or supportoperations 402, 404, and/or 406 of FIG. 4, at least in part.

Memory 612 may be representative of any information storage mechanism orappliance. Memory 612 may include, for example, a primary memory 616 anda secondary memory 618. Primary memory 616 may include, for example, arandom access memory, read only memory, etc. While illustrated in thisexample as being separate from processing unit 610, it should beunderstood that all or part of primary memory 616 may be provided withinor otherwise co-located/coupled with processing unit 610. Secondarymemory 618 may include, for example, same or similar type of memory asprimary memory or one or more information storage devices or systems,such as, for example, a disk drive, an optical disc drive, a tape drive,a solid state memory drive, etc. In certain implementations, secondarymemory 618 may be operatively receptive of, or otherwise configurable tocouple to, a computer-readable medium 620. Computer-readable medium 620may include, for example, any non-transitory storage medium that maycarry or make accessible information, code, or instructions for one ormore of devices in computing environment 600. Computer-readable medium620 may also be referred to as a machine-readable medium, storagemedium, or the like.

Second device 604 may include, for example, a communication interface622 that may provide for or otherwise support an operative coupling ofsecond device 604 to at least communications network 608. By way ofexample but not limitation, communication interface 622 may include anetwork interface device or card, a modem, a router, a switch, atransceiver, and the like. Second device 604 may also include, forexample, an input/output device 624. Input/output device 624 may berepresentative of one or more devices or features that may beconfigurable to accept or otherwise introduce human or machine inputs,or one or more devices or features that may be capable of delivering orotherwise providing for human or machine outputs. By way of example butnot limitation, input/output device 624 may include an operativelyconfigured display, speaker, keyboard, mouse, trackball, touch screen,information port, or the like.

The methodologies described herein may be implemented by various meansdepending upon applications according to particular examples. Forexample, such methodologies may be implemented in hardware, firmware,software, or combinations thereof. In a hardware implementation, forexample, a processing unit may be implemented within one or moreapplication specific integrated circuits (“ASICs”), digital signalprocessors (“DSPs”), digital signal processing devices (“DSPDs”),programmable logic devices (“PLDs”), field programmable gate arrays(“FPGAs”), processors, controllers, micro-controllers, microprocessors,electronic devices, other devices units de-signed to perform thefunctions described herein, or combinations thereof.

Algorithmic descriptions and/or symbolic representations are examples oftechniques used by those of ordinary skill in the signal processingand/or related arts to convey the substance of their work to othersskilled in the art. An algorithm is here, and generally, is consideredto be a self-consistent sequence of operations and/or similar signalprocessing leading to a desired result. In this context, operationsand/or processing involve physical manipulation of physical quantities.Typically, although not necessarily, such quantities may take the formof electrical and/or magnetic signals and/or states capable of beingstored, transferred, combined, compared, processed or otherwisemanipulated as electronic signals and/or states representing variousforms of content, such as signal measurements, text, images, video,audio, etc. It has proven convenient at times, principally for reasonsof common usage, to refer to such physical signals and/or physicalstates as bits, values, elements, symbols, characters, terms, numbers,numerals, measurements, messages, parameters, frames, packets, contentand/or the like. It should be understood, however, that all of theseand/or similar terms are to be associated with appropriate physicalquantities or manifestations, and are merely convenient labels. Unlessspecifically stated otherwise, as apparent from the precedingdiscussion, it is appreciated that throughout this specificationdiscussions utilizing terms such as “processing,” “computing,”“calculating,” “determining”, “establishing”, “obtaining”,“identifying”, “selecting”, “generating”, and/or the like refer toactions and/or processes of a specific apparatus, such as a specialpurpose computer and/or a similar special purpose computing and/ornetwork device. In the context of this specification, therefore, aspecial purpose computer and/or a similar special purpose computingand/or network device is capable of processing, manipulating and/ortransforming signals and/or states, typically represented as physicalelectronic and/or magnetic quantities within memories, registers, and/orother storage devices, transmission devices, and/or display devices ofthe special purpose computer and/or similar special purpose computingand/or network device. In the context of this particular patentapplication, as mentioned, the term “specific apparatus” may include ageneral purpose computing and/or network device, such as a generalpurpose computer, once it is programmed to perform particular functionspursuant to instructions from program software.

In some circumstances, operation of a memory device, such as a change instate from a binary one to a binary zero or vice-versa, for example, maycomprise a transformation, such as a physical transformation. Likewise,operation of a memory device to store bits, values, elements, symbols,characters, terms, numbers, numerals, measurements, messages,parameters, frames, packets, content and/or the like may comprise aphysical transformation. With particular types of memory devices, such aphysical transformation may comprise a physical transformation of anarticle to a different state or thing. For example, but withoutlimitation, for some types of memory devices, a change in state mayinvolve an accumulation and/or storage of charge or a re-lease of storedcharge. Likewise, in other memory devices, a change of state maycomprise a physical change, such as a transformation in magneticorientation and/or a physical change and/or transformation in molecularstructure, such as from crystalline to amorphous or vice-versa. In stillother memory devices, a change in physical state may involve quantummechanical phenomena, such as, superposition, entanglement, and/or thelike, which may involve quantum bits (qubits), for example. Theforegoing is not intended to be an exhaustive list of all examples inwhich a change in state form a binary one to a binary zero or vice-versain a memory device may comprise a transformation, such as a physicaltransformation. Rather, the foregoing is intended as illustrativeexamples.

Wireless communication techniques described herein may be in connectionwith various wireless communications networks such as a wireless widearea network (“WWAN”), a wireless local area network (“WLAN”), awireless personal area network (WPAN), and so on. The term “network” and“system” may be used interchangeably herein. A WWAN may be a CodeDivision Multiple Access (“CDMA”) network, a Time Division MultipleAccess (“TDMA”) network, a Frequency Division Multiple Access (“FDMA”)network, an Orthogonal Frequency Division Multiple Access (“OFDMA”)net-work, a Single-Carrier Frequency Division Multiple Access(“SC-FDMA”) network, or any combination of the above networks, and soon. A CDMA network may implement one or more radio access technologies(“RATs”) such as cdma2000, Wideband-CDMA (“W-CDMA”), to name just a fewradio technologies. Here, cdma2000 may include technologies implementedaccording to IS-95, IS-2000, and IS-856 standards. A TDMA network mayimplement Global System for Mobile Communications (“GSM”), DigitalAdvanced Mobile Phone System (“D-AMPS”), or some other RAT. GSM andW-CDMA are described in documents from a consortium named “3rdGeneration Partnership Project” (“3GPP”). Cdma2000 is described indocuments from a consortium named “3rd Generation Partnership Project 2”(“3GPP2”). 3GPP and 3GPP2 documents are publicly available. 4G Long TermEvolution (“LTE”) communications networks may also be implemented inaccordance with claimed subject matter, in an aspect. A WLAN maycomprise an IEEE 802.11x network, and a WPAN may comprise a Bluetoothnetwork, an IEEE 802.15x, for example. Wireless communicationimplementations described herein may also be used in connection with anycombination of WWAN, WLAN or WPAN.

In another aspect, as previously mentioned, a wireless transmitter oraccess point may comprise a femtocell, utilized to extend cellulartelephone service into a business or home. In such an implementation,one or more mobile devices may communicate with a femtocell via a codedivision multiple access (“CDMA”) cellular communication protocol, forexample, and the femtocell may provide the mobile device access to alarger cellular telecommunication network by way of another broadbandnetwork such as the Internet.

Techniques described herein may be used with an SPS that includes anyone of several GNSS and/or combinations of GNSS. Furthermore, suchtechniques may be used with positioning systems that utilize terrestrialtransmitters acting as “pseudolites”, or a combination of SVs and suchterrestrial transmitters. Terrestrial transmitters may, for example,include ground-based transmitters that broadcast a PN code or otherranging code (e.g., similar to a GPS or CDMA cellular signal). Such atransmitter may be assigned a unique PN code so as to permitidentification by a remote receiver. Terrestrial transmitters may beuseful, for example, to augment an SPS in situations where SPS signalsfrom an orbiting SV might be unavailable, such as in tunnels, mines,buildings, urban canyons or other enclosed areas. Another implementationof pseudolites is known as radio-beacons. The term “SV”, as used herein,is intended to include terrestrial transmitters acting as pseudolites,equivalents of pseudolites, and possibly others. The terms “SPS signals”and/or “SV signals”, as used herein, is intended to include SPS-likesignals from terrestrial transmitters, including terrestrialtransmitters acting as pseudolites or equivalents of pseudolites.

Likewise, in this context, the terms “coupled”, “connected,” and/orsimilar terms are used generically. It should be understood that theseterms are not intended as synonyms. Rather, “connected” is usedgenerically to indicate that two or more components, for example, are indirect physical, including electrical, contact; while, “coupled” is usedgenerically to mean that two or more components are potentially indirect physical, including electrical, contact; however, “coupled” isalso used generically to also mean that two or more components are notnecessarily in direct contact, but nonetheless are able to co-operateand/or interact. The term coupled is also understood generically to meanindirectly connected, for example, in an appropriate context.

The terms, “and”, “or”, “and/or” and/or similar terms, as used herein,include a variety of meanings that also are expected to depend at leastin part upon the particular context in which such terms are used.Typically, “or” if used to associate a list, such as A, B or C, isintended to mean A, B, and C, here used in the inclusive sense, as wellas A, B or C, here used in the exclusive sense. In addition, the term“one or more” and/or similar terms is used to describe any feature,structure, and/or characteristic in the singular and/or is also used todescribe a plurality and/or some other combination of features,structures and/or characteristics. Likewise, the term “based on” and/orsimilar terms are understood as not necessarily intending to convey anexclusive set of factors, but to allow for existence of additionalfactors not necessarily expressly described. Of course, for all of theforegoing, particular context of description and/or usage provideshelpful guidance regarding inferences to be drawn. It should be notedthat the following description merely provides one or more illustrativeexamples and claimed subject matter is not limited to these one or moreexamples; however, again, particular context of description and/or usageprovides helpful guidance regarding inferences to be drawn.

In this context, the term network device refers to any device capable ofcommunicating via and/or as part of a network and may comprise acomputing device. While network devices may be capable of sending and/orreceiving signals (e.g., signal packets and/or frames), such as via awired and/or wireless network, they may also be capable of performingarithmetic and/or logic operations, processing and/or storing signals,such as in memory as physical memory states, and/or may, for example,operate as a server in various embodiments. Network devices capable ofoperating as a server, or otherwise, may include, as examples, dedicatedrack-mounted servers, desktop computers, laptop computers, set topboxes, tablets, netbooks, smart phones, wearable devices, integrateddevices combining two or more features of the foregoing devices, thelike or any combination thereof. Signal packets and/or frames, forexample, may be exchanged, such as between a server and a client deviceand/or other types of network devices, including between wirelessdevices coupled via a wireless network, for example. It is noted thatthe terms, server, server device, server computing device, servercomputing platform and/or similar terms are used interchangeably.Similarly, the terms client, client device, client computing device,client computing platform and/or similar terms are also usedinterchangeably. While in some instances, for ease of description, theseterms may be used in the singular, such as by referring to a “clientdevice” or a “server device,” the description is intended to encompassone or more client devices and/or one or more server devices, asappropriate. Along similar lines, references to a “database” areunderstood to mean, one or more databases and/or portions thereof, asappropriate.

It should be understood that for ease of description a network device(also referred to as a networking device) may be embodied and/ordescribed in terms of a computing device. However, it should further beunderstood that this description should in no way be construed thatclaimed subject matter is limited to one embodiment, such as a computingdevice and/or a network device, and, instead, may be embodied as avariety of devices or combinations thereof, including, for example, oneor more illustrative examples.

References throughout this specification to one implementation, animplementation, one embodiment, an embodiment and/or the like means thata particular feature, structure, and/or characteristic described inconnection with a particular implementation and/or embodiment isincluded in at least one implementation and/or embodiment of claimedsubject matter. Thus, appearances of such phrases, for example, invarious places throughout this specification are not necessarilyintended to refer to the same implementation or to any one particularimplementation described. Furthermore, it is to be understood thatparticular features, structures, and/or characteristics described arecapable of being combined in various ways in one or more implementationsand, therefore, are within intended claim scope, for example. Ingeneral, of course, these and other issues vary with context. Therefore,particular context of description and/or usage provides helpful guidanceregarding inferences to be drawn.

While there has been illustrated and described what are presentlyconsidered to be example features, it will be understood by thoseskilled in the art that various other modifications may be made, andequivalents may be substituted, without departing from claimed subjectmatter. Additionally, many modifications may be made to adapt aparticular situation to the teachings of claimed subject matter withoutdeparting from the central concept described herein. Therefore, it isintended that claimed subject matter not be limited to the particularexamples disclosed, but that such claimed subject matter may alsoinclude all aspects falling within the scope of the appended claims, andequivalents thereof.

1. A method, at a mobile device, comprising: storing observations of radio frequency (RF) signals transmitted from one or more wireless transmitters in an area, the observations being stored based, at least in part, on one or more associations between the observations and one or more sensor measurements obtained from one or more on-board sensors; and processing the observations to obtain an estimate of a location of the mobile device based, at least in part, on the one or more associations and responsive to a request for the estimate occurring subsequent to the storing the observations.
 2. The method of claim 1, wherein the observations are processed based, at least in part, on positioning assistance data obtained subsequent to the storing the observations.
 3. The method of claim 2, wherein the positioning assistance data comprises one or more positioning tiles covering at least a portion of the area.
 4. The method of claim 1, wherein the one or more associations comprise at least one of: a time-related association; a location-related association; a parameter-related association, or any combination thereof.
 5. The method of claim 1, wherein the observations are stored in one or more measurement batches in a local memory of the mobile device.
 6. The method of claim 5, wherein the processing further comprises accessing the local memory to retrieve at least one of the one or more measurement batches via correlating the observations with one or more subsequent observations of the one or more wireless transmitters in the area.
 7. The method of claim 6, wherein the one or more subsequent observations comprise observations obtained subsequent to the request for the estimate of the location of the mobile device.
 8. The method of claim 5, wherein a particular measurement batch of the one or more measurement batches is stored with reference to at least one of: a particular location within the area; a particular time period for observing the RF signals; a particular parameter of the RF signals, or any combination thereof.
 9. The method of claim 1, wherein the request for the estimate of the location comprises a message initiating a positioning session for the mobile device.
 10. The method of claim 9, wherein the message is indicative of an emergency event comprising a 911 call originating from the mobile device.
 11. The method of claim 1, wherein the area comprises a satellite positioning system (SPS)-denied environment.
 12. The method of claim 1, wherein the observations comprise at least one of: time-stamped observations; geo-tagged observations, or any combination thereof.
 13. The method of claim 1, wherein the observations comprise at least one of: a measured time of arrival (TOA) of the RF signals; a measured time difference of arrival (TDOA) of the RF signals; a received signal strength indicator (RSSI) measurement of the RF signals; a round-trip time (RTT) measurement of the RF signals; an identity of the one or more wireless transmitters, or any combination thereof.
 14. The method of claim 1, wherein the one or more wireless transmitters comprise at least one of: a Wi-Fi access point; a cellular base station; a femtocell; a picocell, or any combination thereof.
 15. The method of claim 1, wherein the observations are obtained via a scan of the area.
 16. The method of claim 1, wherein the processing further comprises de-weighting the observations based, at least in part, on an age of the observations.
 17. The method of claim 1, and further comprising estimating the location of the mobile device in the area based, at least in part, on a location of at least one of the one or more wireless transmitters determined based, at least in part, on the one or more associations and one or more subsequent observations of the RF signals in the area.
 18. The method of claim 1, and further comprising: associating the one or more sensor measurements with the observations based, at least in part, on at least one of: a particular location within the area; a particular time period for observing the RF signals; a particular parameter of the RF signals, or any combination thereof.
 19. An apparatus comprising: a communication interface coupled to a receiver of a mobile device to communicate with an electronic communications network and one or more processors coupled to a memory and to the communication interface, the communication interface and the one or more processors configured to: store observations of radio frequency (RF) signals transmitted from one or more wireless transmitters in an area, the observations being stored based, at least in part, on one or more associations between the observations and one or more sensor measurements obtained from one or more on-board sensors; and process the observations to obtain an estimate of a location of the mobile device based, at least in part, on the one or more associations and responsive to a request for the estimate occurring subsequent to the storing the observations.
 20. The apparatus of claim 19, wherein the one or more processors are further configured to process the observations based, at least in part, on positioning assistance data obtained subsequent to the storing the observations.
 21. The apparatus of claim 20, wherein the positioning assistance data comprises one or more positioning tiles covering at least a portion of the area.
 22. The apparatus of claim 19, wherein the one or more associations comprise at least one of: a time-related association; a location-related association; a parameter-related association, or any combination thereof.
 23. The apparatus of claim 19, wherein the observations are stored in one or more measurement batches in a local memory of the mobile device.
 24. The apparatus of claim 23, wherein the one or more processors are further configured to access the local memory to retrieve at least one of the one or more measurement batches via correlating the observations with one or more subsequent observations of the one or more wireless transmitters in the area.
 25. The apparatus of claim 23, wherein a particular measurement batch of the one or more measurement batches is stored with reference to at least one of: a particular location within the area; a particular time period for observing the RF signals; a particular parameter of the RF signals, or any combination thereof.
 26. The apparatus of claim 19, wherein the observations comprise at least one of: time-stamped observations; geo-tagged observations, or any combination thereof.
 27. The apparatus of claim 19, wherein the one or more processors further configured to de-weight the observations based, at least in part, on an age of the observations.
 28. The apparatus of claim 19, wherein the one or more processors further configured to estimate the location of the mobile device in the area based, at least in part, on a location of at least one of the one or more wireless transmitters determined based, at least in part, on the one or more associations and one or more subsequent observations of the RF signals in the area.
 29. The apparatus of claim 19, wherein the one or more processors further configured to: associate the one or more sensor measurements with the observations based, at least in part, on at least one of: a particular location within the area; a particular time period for observing the RF signals; a particular parameter of the RF signals, or any combination thereof.
 30. A non-transitory storage medium having instructions executable by a processor to: store observations of radio frequency (RF) signals transmitted from one or more wireless transmitters in an area, the observations being stored based, at least in part, on one or more associations between the observations and one or more sensor measurements obtained from one or more on-board sensors; and process the observations to obtain an estimate of a location of a mobile device based, at least in part, on the one or more associations and responsive to a request for the estimate occurring subsequent to the storing the observations. 